Embodiments relate to a light emitting device, a light emitting device package, and a lighting system.
Light emitting diodes (LEDs) are a kind of semiconductor device for converting electric energy into light. LEDs may realize various colors by adjusting a composition ratio and material of compound semiconductors.
In such an LED, when a forward voltage is applied, electrons of n-layer are combined with holes of a p-layer to generate light energy corresponding to an energy gap between a conduction band and a valance band.
Nitride semiconductors that are a kind of material constituting LEDs are attracting much attention for the fields of optical devices and high-power electronic devices because of their high thermal stability and wide band gap energy. Specifically, blue LEDs, red LEDs, green LEDs, and UV LEDs which use nitride semiconductors are being commercialized.